pgfplotsdemo.tex

\documentclass[border=2mm]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{positioning, calc, fit, backgrounds}
\pgfplotsset{
  miniaxis/.style={
    scale only axis,
    width=8mm,
    height=6mm,
    axis lines=left,
    axis line style={-},
    xtick=\empty,ytick=\empty,
    after end axis/.code={
     \scoped[on background layer]
      \node [block, fit=(current axis), #1] {};
     }
  }
}
\begin{document}
\begin{tikzpicture}[
    PIctrl/.style={
        append after command={
             \pgfextra{\let\lastnode\tikzlastnode} 
            ($(\lastnode.south west) + (0.5em,0.5em)$) edge
            ($(\lastnode.south east) + (-0.5em,0.5em)$) edge
            ($(\lastnode.north west) + (0.5em,-0.5em)$) edge[-, very thick]
            ($(\lastnode.north west) + (0.5em,-1.5em)$)
            ($(\lastnode.north west) + (0.5em,-1.5em)$) edge[-, very thick]
            ($(\lastnode.north east) + (-0.8em,-0.8em)$)
        }
    },
    blockheight/.style = {
        minimum height=10mm
    },
    block/.style={
        draw,
        % The shape:
        rectangle, minimum size=6mm, minimum width=12mm,
        blockheight,
        node distance=5mm,
    },
    every node/.style = {font=\sffamily},
    every label/.style={
        font=\sffamily\scriptsize
    },
    >=latex
      ]
      
\node[block, PIctrl, label={below:PI controller}] (block1) at (0,0) {};

\begin{axis}[
  miniaxis={name=block2,label=below:bounded reciprocal},
  at={($(block1.east) + (1cm,0)$)},
  anchor=west,
  ymin=0
  ]
\addplot[domain=0.17:0.55, smooth, black, dash pattern = {on 0.5mm off 0.5mm}, dash phase=0.9mm ] {0.25/x};
\addplot [domain=0:1.8, samples=40, smooth, black, thick ] {0.25/max(x,0.3)};
\end{axis}

\draw [->] (block1) -- (block2);

\end{tikzpicture}
\end{document}